Improve resource leftovers

There are two things here that are both aimed at reducing the amount of
resource clutter:

1. I've seen many tmp files left.  Looking at the code, it seems to me
   like a reasonable thing to get rid of them when a file is saved.  I
   did this via adding `tide-remove-tmp-file` on `after-save-hook`.

2. I also saw that there is a general tendency to accumulate many
   servers since they're never removed (actually, more than just the
   servers -- the whole project resources are kept, but the server is
   the main problem wrt resources).  This is also mentioned in #256.

   So I implemented a function that scans all buffers and cleanup all
   projects that have no live buffers.  It looks to me like a good idea
   to do this, since you can just kill old buffers to reduce resource
   usage.  (And killing old buffers is more obvious than explicitly
   openning the server list to kill old ones, especially since there's
   no way to tell if a server is used by some buffer or not.)

   (I added this function onto `kill-buffer-hook`, but if that's too
   extreme, then a more mild option is to not do that and just let
   people add it themselves.)

Author: elibarzilay

tide.el

@@ -729,6 +729,16 @@ If TIDE-TSSERVER-EXECUTABLE is set by the user use it.  Otherwise check in the n
   (remhash project-name tide-tsserver-unsupported-commands)
   (remhash project-name tide-project-configs))
 
+(defun tide-cleanup-dead-projects ()
+  (let ((live-projects '()))
+    (dolist (b (buffer-list))
+      (-when-let (proj (with-current-buffer b
+                         (and (bound-and-true-p tide-mode)
+                              (tide-project-name))))
+        (cl-pushnew proj live-projects)))
+    (dolist (proj (-difference (hash-table-keys tide-servers) live-projects))
+      (tide-cleanup-project proj))))
+
 (defun tide-start-server-if-required ()
   (unless (tide-current-server)
     (tide-start-server)))
@@ -1953,15 +1963,19 @@ code-analysis."
       (progn
         (add-hook 'after-save-hook 'tide-sync-buffer-contents nil t)
         (add-hook 'after-save-hook 'tide-auto-compile-file nil t)
+        (add-hook 'after-save-hook 'tide-remove-tmp-file nil t)
         (add-hook 'after-change-functions 'tide-handle-change nil t)
         (add-hook 'kill-buffer-hook 'tide-cleanup-buffer nil t)
+        (add-hook 'kill-buffer-hook 'tide-cleanup-dead-projects nil t)
         (add-hook 'hack-local-variables-hook 'tide-configure-buffer nil t)
         (when (commandp 'typescript-insert-and-indent)
           (eldoc-add-command 'typescript-insert-and-indent)))
     (remove-hook 'after-save-hook 'tide-sync-buffer-contents t)
     (remove-hook 'after-save-hook 'tide-auto-compile-file t)
+    (remove-hook 'after-save-hook 'tide-remove-tmp-file t)
     (remove-hook 'after-change-functions 'tide-handle-change t)
     (remove-hook 'kill-buffer-hook 'tide-cleanup-buffer t)
+    (remove-hook 'kill-buffer-hook 'tide-cleanup-dead-projects t)
     (remove-hook 'hack-local-variables-hook 'tide-configure-buffer t)
     (tide-cleanup-buffer)))